Electric switch



Oct. 26, 1948. D. E. MORAN ETAL 2,452,065

Y ELECTRIC swrrcu Filea Dec. :50, 194: 2 Sheets-Sheet 1 Fig. I.

v pafirllrallzirlllaln 1 Inventor's: Don E. Moran, Samuel F. Jarvis.

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Ott. 26, 1948. D. E. MORAN ErAL ELECTRIC SWITCH 2 Sheets-Sheet 2 FiledDec. 30. 1943 (,1 C Inventor-s: Don LMQran. Samuel F Jarvis b ,6 W TmAttorngg.

Patented Oct. 26, 1948 ELECTRIC SWITCH Don E. Moran and Samuel F.Jarvis, Schenectady, N. Y., assignors to General Electric Company, acorporation of New York Application December 30, 1943, S ierial No.516,260

4 Claims. 1

Our invention relates to electric switches, more particularly toelectromagnetically operated switches, and has for its object a reliableand inexpensive switch which is free from operation by heavy shocks.

When electromagnetically operated switches are subjected to heavy shocksat the time themagnet is energized and the armature is in a normalattracted position against the stationary magnet frame, the shock hasthe effect of throwing the armature away from the magnet frame towardits unattracted position. This occurs against the magnetic force holdingthe armature in its attracted position. The type ofshock contemplated isone that is applied to the body on which the switch is mounted, such asa shock caused by a nearby explosion. The effect of such a shock isapplied from the supporting body to the magnet frame of the magnet andtransmitted by the frame to the armature whereby the armature is thrownaway against the magnetic force holding it in its attracted position.

In accordance with our invention, we prevent the transmission of theforce of the shock from the magnet frame to the armature by bringing thearmature to rest in its attracted position before it has moved farenough to engage the magnet frame. This we accomplished by providingstopping means for bringing the armature to rest in its attractedposition before it engages the magnet frame. Moreover, our means forbringing the armature to rest does not have the rebound characteristicreferred to when subjected to a shock. In one form of our invention weprovide friction braking means for engaging the armature as itapproaches its attracted position and for applying an increased brakingforce as the armature continues its movement thereby to bring the'armature to rest in spaced relation with the magnet frame.

Our invention relates also to bus transfer switching means and, inaccordance therewith, we provide'electromagnetic means for normallyoperating the switching means together with manual means fordeenergizing the electromagnetic means and for manually operating saidtransfer'switching means. I

For a more complete understanding of our invention, reference should behad to the accompanying drawing, Fig. 1 of which is a bottom viewlooking up of a two-way electromagnetically operated switch embodyingour invention; Fig. 2

is a view mainly in section taken along the line 2-2 of Fig. 3 lookingin the direction of the arrows; Fig. 3 is an end view of the dev ceshown 2 in Fig. 1; Fig. 4 is an exploded view in perspective showing thevarious operating parts of the device; while Fig. 5 is a, wiring diagramshowing the application of our invention as a changeover switch fortransferring the connections of a load from one supply source to anotherautomatically in response to a predetermined decrease in the voltage ofone supply source.

Referring to the drawings, we have shown our invention in one form asapplied to a doublethrow bus transfer switching means comprising the twothree-pole switches or contactors l0 and H (Figs. 4 and 5) which areshown diagrammatically. As shown in Fig. 5, these switches arecontrolled selectively to connect the load connections l2 to either asupply source l3 or a supply source H, the load and supply circuitsbeing indicated as three-phase. The operating coils l5 and I8 for thetwo switches are controlled by a two-way selector switch H which in turnis operated by a control motor device I8 connected to the supply sourceit. The control device 18 is responsive to the voltage of the source Hto energize the coil l8 when the voltage of the source ll drops to apredetermined minimum value thereby to disconnect the load circuit i2from the supply source, while at the same time the coil i5 isdeenergized to close the switch It! and thereby connect the load circuitto the supply source l3.

As shown, particularly in Fig. 4, the coils IE and it are provided withstationary magnet frames i9 and 20 and with plunger armatures 2i and 22.These armatures are connected through links 28 and 2 to a lever arm 25secured at its center to one end of a pivot shaft 26. Connected to theends of the arm 25 by means of suitable pin and slot connections arereciprocating slider members 21 and 28, shown as cylindrical plungers,

which are mounted in suitable cylindrical guides in the support 28 forthe mechanism. Thus, as shown in Fig. 2, the slider member 28 isslidably mounted in a cylindrical support 30.

For the operation of the switches Ill and l l the sliders 21 and 28 areprovided with cut away portions forming cam surfaces 3i and 32 withwhich cooperate rollers 33 and 3 on the ends of switch operatingplungers 35 and 36 to which the switches l0 and II are directlyconnected. As shown in Fig. 4, the coil I5 is deenergized while the coili6 is energized and has moved the arm 25 clockwise, as seen in Fig.4,-and pulled downward its right-hand end. This action causes the camsurface 5| in moving upward to push the rod 35 toward the right, therebyopening the switch Hi. This movement of the rod 35 is transmittedthrough a lever 81 to the plunger 38 in the reverse direction'so thatthe plunger 88 is moved toward the left whereby the switch ii is closed.The lever 81 has a fixed pivot 88 at its center on a stationary support.89, and its ends are connected through pin and slot connections 48 and4| to the two plungers.

It will be understood that when the coil I8 is deenergized and the coili5 is energized, the lever 25 is moved counterclockwise on its pivotshaft 28 thereby to open the switch II and close the switch l8.

For the purpose of stopping the plunger armatures 2| and 22 before theyengage and seat against their magnet frames I8 and 20, we have providedfriction braking means associated with the two slider members 21 and 28,comprising two pivoted braking and stop members 42 and 48 mountedadjacent their upper ends, as shown clearly in Fig. 2, on stationarypivots 44 and 45. This braking means is particularly described andclaimed in our copending divisional application Serial No. 702,290,filed October 8, 1946, and as-' signed to the same assignee as thepresent application. Referring particularly to Fig. 2, thebivotedbraking member 48 is provided with a projection or extension 46 on itslower end extending toward the right into a recess in the lower end ofthe member 28. This recess or cut away portion in the lower end of themember 28 provides a portion 41 on its lower end presenting a flatsurface or side wall to the laterally extending end projection 45 of thepivoted member, this surface lyin in a plane parallel with the length ofthe member 28. Also, at the upper end of this portion 41 is a shoulder48 forming an abutment lying in a plane at right angles to the length ofthe member 28.

Continuing with reference to Fig. 2, on the pivoted braking member 48,specifically on the portion 45, are projections 49 and 50 which engagerespectively the plane surfaces on the shoulder 48 and the portion 41.The projection 49 is rigidly secured on the pivoted member while theprojection 50 is yieldable and is in reality, as shown, a plungerslidably mounted in a cylindrical recess 5| in the portion 48 andpressed outward by a helical spring 52. A screw 53, whose inner endprojects into an annular groove 54 on the plunger 50, limits the outwardmovement of the plunger by the spring. Also, at its upperend at a pointabove and to the right of the pivot 45, the pivoted member has aprojection 55 in position to engage the side of member 28 when themember 43 is moved clockwise on its pivot 45. As seen in Fig. 2, thecylindrical guide or support 80 for the member 28 is provided with aslot 58 through which extends the projections 48 and 55 on the member43.

As shown in Fig. 2, the member or plunger 28 is in its lowermostposition in engagement with the projections 49 and 58. Its engagementfirst with the projection 58 has turned the member 43 clockwise aboutits pivot 45 and thereby swung the projection 55 with a force dependentupon the strength of the spring 5| against the side of the member 28.The pressure thus applied by the projection 55 forces the member 28toward the right, as seen in Fig. 2, tightly against the wall of itsguide 80, thereby producing a frictional braking eflect between the twoas well as producing a frictional braking effect directly between theprojection 55 and its point of engagement with the member 28. Also theprojection 49 when engaged during the final movement of the member 28increases the frictional braking effect and ultimately acts as apositive abutment stop for the member 48. This brings the member 28 torest in a, position in which the lower end of the armature 22 is stillin spaced relation with the magnet frame, as shown in Fig. 4.,Therefore, shocks applied to the support for the device and transmittedfrom the support to the magnet frame or components of these shocks in anupward direction, as seen in the drawing, are not applied to the plungerarmature 22, the magnet frame 25 moving 'upward independently of thearmature and relative thereto. Consequently, the shock has no effect inproducing turning movement of the lever 25 and operation of theswitches.

This upwardly directed shock will not throw the slidable member 27 northe member 28 from its latched position, as shown in Fig. 2, for thereason thatthe slidable member is held in this predetermined lowermostposition by the relatively. great friction between it and its guide 88,which friction is produced as previously described .by means of thepivoted looking or braking member 42 or 48. Also, it will be observedthat because the various parts of the device that are rigidly connectedtogether will be moved by a shock upward together, as well as in otherdirections, then the pivot shaft 28 and the plungers and 88 will bemoved upward together by the shock whereby )the arm 25 is lifted, andwith it lifted the plungers 2| and 22 at the same time that the magnetframes are lifted by the shock. This action thus serves to maintain apredetermined air gap between the lower end of the particular plunger,at that time in its attracted position, and the magnet frame.

It will be understood that the switches l8 and It may be of any suitabletype although they are shown diagrammatically in the drawing for thepurpose of clarity.

As shown in Fig. 3, the operating mechanism thus far described ismounted on a supporting base or plate 51, the magnet frames, armaturesand slidable members 21 and 28 being mounted below the plate 51 with theplungers 35 and 35 extending upward through apertures in the plate andwith the connecting lever 81 mounted above the plate. This mechanism, asshown in Fig. 3, is preferably, as shown in Fig. 1, fitted into an openbottom casing 29. On the top of this casing are mounted the switches l8and I I.

We have also provided manual means for operating the switches throughthe lever mechanism.- This manual operating means comprises a knob 58mounted on a shaft 59 which is supported on the top wall of theenclosing casing 28, the shaft being biased outward from the casing by ahelical spring 68. Inside the casing the end of the shaft 59 is providedwith a transversely extending clutch member or blade 8|. ,On the end ofthe pivot shaft 28 is a channel-shaped member 82 which is rigidlysecured at its center to the shaft 28 and turns with the shaft. Thechannel member is wide enough,'however, to provide a loose connece tionwith the blade 8|. which lies between the sides of the channel so thatthe shaft 28 is freewhen the knob 58 is depressed manually, the blade BIis forced out of the central pair of notches and then the knob can beturned in the appropriate direction to bring the blade into engagementwith the side walls of the channel member and operate the switch to thedesired position. The knob can then be released to provide for movementof the shaft 59 outward by the spring and the locking-of the blade Si inthe pair of notches corresponding 'to its position whereby the switch islocked in the position to which it has been operated. It will beunderstood that the side walls of the channel member are high enough toprovide for this lateral movement of the blade 6| while the blade stillremains between the side walls.

Also, to assure deenergization of the coils i5 and I8 when manualoperation is resorted to. one end of the blade Si is provided with acurved operating cam 64 which, when the ,knob 58 is in an intermediateposition, bears on a switch rod 85 and forces it upward to hold closedthe two switches 66 and 61. These switches, as shown in Fig. 5, are inthe circuits of the operating coils. When the handle is turned from themid position, the cam 64 moves to one side of the switch rod 85 wherebythe switch is opened to open the circuits of the coils.

This manual operation of the switch by .the knob 58 permit-s operationof it in the event that the voltage responsive device t8 fails tooperate the switches or in the event the operator desires to transferthe load from one circuit to the other, regardless of the voltageconditions.

In Fig. 1 .the voltage responsive motor I8 is shown mounted in thecasing in a position adjacent the switch operating mechanism. It will beunderstood that this motor, provided with two coils 68 and 59 connectedacross two phases of the supply source it, is connected permanently tothe supply source H so as to be energized at all times. The rotor of themotor thereby under normal voltage conditions has a torque applied to itsufiicient to return it to a predetermined position against the forceapplied by a biasing spring (not shown). When the voltage decreases to apredetermined minimum value, however, the torque applied to the rotordecreases and the spring thereupon turns the rotor back to'its otherpredetermined position, shown in Fig. 5, in which the switching devicei1 is in position to energize the coil i8 to open the switch II anddeenergize the coil E5 to close the switch l0. As shown, the switchingdevice i1 is mounted on a pivot 10 and is provided with a forked portionH embracing an eccentric i2 operated by the motor.

While we have shown a particular embodiment of our invention, it will beunderstood, of course, that We do not Wish to be limited thereto sincemany modifications may be made, and we therefore contemplate by theappended claims to cover any such modifications as fall within the truespirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States, is:

1. An electric switch comprising a movable switch member, an operatingmember movable to operate said switch member, said operating memherbeing provided with an abutment, electromagnetic actuating means forsaid operating member including an armature connected to said operatingmember and a stationary magnet frame for said armature, an operatingcoil on said magnet frame, a pivoted member extending in the directionof movement of said op rating member,

a laterally extending projection on said pivoted member positioned to beengaged by said abutment when said operating member approaches the limitoi its movement when said coil is energized to move said armature to itsattracted position whereby said pivoted member is moved on its pivot,braking means operated by said pivotai movement of said pivoted memberfor engaging said operating member thereby to apply a frictional brakingforce to said ope at ber whereby'said operating member is brought torest by said projection in a predetermined position with said armaturein spaced relation with said magnet frame.

2. An electric switch comprising two movable switch members, stationarycontacts with which said switch members cooperate, a plunger foroperating each of said movable switch' members, a longitudinall movablecam member-cooperating with each of said plungers provided with a camsurface for moving its plunger longitudinally upon longitudinal movementof said cam member, a pivoted braking member pivotally mounted adjacenteach of said cam members, a projection on each of said braking membersengaged by its said cam member in abutting relation therewith thereby tobring said cam member to rest in a predetermined position, a secondprojection on each of said braking members on the opposite side of thepivot of said braking member from said first projection for frictionallyengaging its said cam member when said braking member is moved by saidcam member, a lever forming a mechanical connection between said cammembers, and electromagnetic means including movable armature meansconnected to said lever for effecting movement of said cam members inopposite directions and operation of said switch members between theiropen and closed positions, said braking members operating alternatel tobring said cam members to rest in predetermined positions thereby tolimit the movement of said armature means.

3. An electric switch comprising two movable switch members, stationarycontacts with which said switch members cooperate, a. plunger foroperating each of said movable switch members, a longitudinally movablecam member cooperating with each of said plungers provided with a camsurface for moving its plunger longitudinally upon movement of said cammember, each of said cam members being formed at one end to provide aplane surface at right angles with the direction of movement of the cammember and a second plane surface at right angles with said first planesurface, a pivoted braking member pivotally mounted adjacent each ofsaid cam members, a projection on said braking member engaging saidfirst plane surface in abutting relation therewith, a spring pressedmember on. said projection engaging said second plane surface inabutting relation therewith, a second projection on each of said brakingmembers on the opposite side of the pivot of said braking member fromsaid first projection for frictlonally engaging the side of said cammember when said cam member is moved into engagement with said brakingmember, a lever forming a mechanical connection between said cammembers, and electromagnetic means including movable armature meansconnected to said lever for effecting movement of said cam members inopposite directions and operation of said switch members between theiropen and closed positions, said braking members operating alternately tobring said cam members to rest in predetermined position thereby tolimit the movement of said armature means.

4. The combination with a magnet provided with a magnet frame, a, coil,and an armature movable from an' unattracted \position to an attractedposition in spaced relation with said magnet frame, of a plungerconnected to said armature so as to move with said armature betweenunattracted and attracted positions, a guide wall for said plunger, abraking and stop member for said plunger pivotally mounted adjacent oneend of said plunger, a spring pressed projection on one end of saidbraking member arranged to engage a side wall of said plunger as saidplunger moves toward its attracted position thereby to move the oppositeend of said braking member into engagement with a side wall of saidplunger and apply a frictional braking force to said plunger, and asecond rigid pro- Jeotion on said braking member engagedby said plungerto bring said plunger and armature to 8 rest with said armature in saidspaced relation with said magnet core.

" DON E. MORAN.

SAMUEL F. JARVIS.

nnraannons crran The following references are of record in the file ofthis patent:

UNITED STATES PATENTS W00d et al Feb. 14, 1939

